Wear reduction additives



D. KATZ Jan. 9, 1968 WEAR REDUCTION ADDITIVES Filed Jan. 2%, 1966 FIG.I.

DANIEL KATZ FIG.3.

United States Patent 3,362,328 WEAR REDUCTION ADDITIVES Daniel Katz,Long Island City, N.Y., assignor to the United States of America asrepresented by the Secretary of the Army Filed Jan. 24, 1966, Ser. No.523,015 9 Claims. (Cl. 10238) ABSTRACT OF THE DHSCLOSURE Fibers ofpolyester, acrylic, silk, wool, glass, and asbestos, when incorporatedin a dispersion of wax containing an erosion-resistant-forming substancesuch as CaSO or CaCO or either combined with TiO and applied to sheetsin propellant systems, will improve brittleness and tackiness propertiesof the treated sheets approaching 40 F. and +145 F. respectively as wellas to prevent damage to fins (of fin stabilized projectiles) when thefins contact the propellant.

The invention described herein may be manufactured and used by or forthe Government for governmental purposes without payment to me of anyroyalty thereon.

This invention relates generally to ordnance items and more particularlyconcerns fiber additives for sheets which are incorporated intocartridges and shells for improving physical properties of the sheetswhen subjected to varying environmental conditions.

In U.S. Patent No. 3,148,620, Jacobson et al. deal with the problem ofexcessive gun barrel wear caused by ignition of propellant producing hotgases which pass through the barrel.

In U.S. Patent-No. 3,282,215, issued to Milton Roth for Additives forReduction of Gun Wear, assigned to the same assignee hereof, variousinexpensive and readily available additives are disclosed forefiiciently reducing gun barrel erosion when the additives areincorporated or dispersed within a wax carrier to form a sheet for usein cartridges and shells.

In both of the aforementioned, the wax becomes undesirably brittle atlow temperatures and excessively tacky at higher temperatures. When waxsheets are incorporated into ammunition and then subjected to standardsimulated transportation tests at environmental extremes, the wax has atendency to coat the propellant in contact therewith, particularly atelevated temperatures, and to cause degradation of ballisticperformance. When fin stabilized rounds are employed where the fins arein the propellant, erratic flights have occurred due to propellantclumping causing fin damage.

In prior ammunition where the wax sheet is necessarily assembled at thefiring site, the wax sheet comprising cloth, wax, and additive, I havefound that at a temperature of 40 F., the resultant sheet was toobrittle to be readily assembled. Further, housekeeping problems areposed in processing the wax sheet, and in ammunition plants where thesheets are inserted into cartridges of various types due to thebrittleness of wax which yields accompanying debris.

Attempts were made to eliminate the aforementioned difficulties byreplacing wax, either partially or wholly, with elastomeric materialssuch as polyethylene, polyurethane, and the like, but their incompletecombustibility or cost rendered the attempts generally abortive.

It is therefore a broad object of this invention to reduce erosion orwear in ordnance members subjected to hot gases of burning propellants.

Another object of the invention is to reduce erosion or wear in gunbarrels of weapons wherein the propellant is partially surrounded by awax carrying sheet.

A further object of the invention is to provide a fiber structure withina wax sheet surrounding ammunition propellant to permit the sheet andammunition to successfully withstand environmental extremes.

The exact nature of the invention as well as other objects andadvantages thereof will be readily apparent from consideration of thefollowing specification relating to the annexed drawing wherein:

FIG. 1 is a front elevation view, partly broken away, of a cartridgeembodying the preferred additive of the present invention,

FIG. 2 is a view of an unfolded sheet utilized in the cartridge of FIG.1, and

FIG. 3 is a partially sectioned view of a cartridge hav ing a finnedprojectile wherein fins contact propellant.

The erosion resistant forming substances comprises a salt such as CaSOor CaCO or either combined with TiO all as described in the patent toRoth, supra, and dispersed in a carbonaceous carrier material such asparafi'in or microcrystalline waxes or other hydrocarbons meltingbetween about to 200 F.

The part of the sheet comprising the chemical additive or additivesdispersed in the wax which is impregnated in a textile adjacent thefront part of the charge is more effective than the sheet adjacent therear end of the charge. Determination of the minimum sheet thickness canbe readily computed from the formula set forth in the patent to Jacobsonet al. supra:

IWE mg./cm.

where C is the calibre of the firearm in cms.; and c-m. refers to thearea of the sheet. By sheet, I refer to my fibers along with theadditives incorporated or dispersed. within the wax carrier, includingthe textile or fabric upon which it is coated or impregnated.

The formula given above may be expressed more generally so that itapplies to all substances as follows:

30 /C gram calories per sq. cm. of sheet surfacethat is the substance issuch that in reacting with the propellant gases it absorbs 30 /C gramcalories per sq. cm. of the sheet surface.

I have obtained good results by dispersing my fibers along with aselected additive or additives, in fine particle size throughout the waxand applying the mixture on fabric covering the charge.

One form of my invention is illustrated in FIG. 1 wherein a cartridge isshown having a metal case 10, propellant charge 12 comprised of asuitable propellant and a projectile 14. Within case 10 and in contactwith the inner surface thereof is a textile wrap 16 which may be of anysuitable material such as rayon (preferred), cotton, silk or otherconventional materials. The upper section of wrap 16 has a plurality ofvertical slits 18 (FIG. 2) through part of its length which form flaps20 as shown in FIG. 1.

Textile 16 is coated, or coated and impregnated with my fiber-additivelayer 22 dispersed in the above-described wax. The fibers may be naturalor synthetic in origin and organic or inorganic in composition. Fibersof organic origin such as Dacron, a polyester fiber, and Orlon, anacrylic fiber, both manufactured by E. I. du Pont de Nemours, or silk orwool fibers, and inorganic fibers such as glass fibers or asbestosfibers, have been found to work admirably well in helping achieve theobjects of the present invention. Nylon fibers or cellulose fibers arenot considered as satisfactory as they are known'to break down uponexposure to oxides of nitrogen for-med from propellant aging. The fiberswill preferably be between additive. Thus, layer 22 will comprise myfibers dispersed within a wax carrier along with the chemical additiveCaSO or CaCO or either combined with TiO or any of the known chemicaladditives for reducing gun barrel erosion. It is preferred that thechemical additive be of a very fine particle size, such as that of talc,for example. Flaps 20 and the additive layer 22 are adapted to be foldedin overlapping manner over the upper surface of the propellant charge12.

The additive coating is prepared by melting the wax and thereaftermixing with my fibers and the additive in proportions hereinafterdescribed. Next, the coating is applied to the fabric in the desiredthickness and permitted to cool and thus formin my sheet.

Coated fabric 16 which is preferably one-half to fivesixths the lengthof the charge, may be wrapped around the propellant 12 or it may be heldin position in the cartridge as the propellant material is poured in. Ifdesired, fabric 16 may be secured to the inner wall of the case by glueor other suitable means so as to retain the coated fabric in position.Thereafter flaps 2d are folded over and projectile 14 is placed on topof the fiaps as shown in FIG. 1.

My fibers are effective in shells of approximately 76 mm. size to thelargest artillery ammunition and are intended to be used on fixed,semifixed, separated or separate-loading types of ammunition. The amountand thickness of my fiber-additive sheet will depend upon the size ofammunition with which it is employed and may readily be calculated fromthe aforementioned formula. In 105 mm. high explosive anti-tank shells,for example, my fibers will permit rougher handling of the shellswithout the wax sheet crumbling and physically deteriorating. Inammunition for a 175 mm. gun, for example, where sheets will beassembled at the firing site, my fibers pro vide for maximum flexibilityof the sheet and ease of handling thereof under severe environmentalconditions.

In the data presented below, the sheet was intended for use on 105 mm.high explosive anti-tank ammunition. Textile 16 was a piece of spunrayon cloth which was resin-treated in order to render the clothresistant to water and to oxides of nitrogen degradation. The rayon wasplaced on a smooth surface and a mixture of my fibers with chemicaladditives poured thereon and spread evenly by scraping with a blade andresulted in a sheet slightly under inch in thickness.

0f course it will be understood that other textiles may be usedadvantageously and my fiber and additives may be impregnated therewithinas well as produce a coating of specified thickness. The propellant usedwas triplebased.

ENVIRONMENTAL DATA problems at both temperature extremes. Percentage findamage was obtained by photographing shells coming out of the gun. Nofins or broken fins comprised fin damage in the table above.

In FIG. 3 of the drawings, a 105 mm. high-explosive anti-tank shell isillustrated, wherein fins 24 are in direct contact with propellant 12.My fiber-additive sheet 22 is shown surrounding propellant 12. In actualfiring tests, my sheets did not degrade ballistic performance, nor tendto clump the propellant to cause fin damage, nor present housekeepingproblems formed by debris.

It will be understood, of course, that my fibers may be employed singly,or in any combination and yet achieving the objects of the invention, solong as the total fiber content remains substantially within the limitsaforedescribed.

Reference is hereby made to patent application, Ser. No. 522,796, ofJean P. Picard, for Erosion Reducer, filed Ian. 24, 1966, and to acontinuation-in-part appli- 0 cation thereof by Jean P. Picard, forErosion Reducer,

filed Jan. 20, 1967, both applications being assigned to the sameassignee of this patent application.

I claim: 1. In a propellant system including: means for containingpropellant, and a sheet surrounding at least an upper half of saidpropellant, said sheet comprising a pervious material impregnated andcoated with a dispersion of Wax and a wear reducing chemical additive,the combination therewith of the improvement for reducing brittleness atlow temperatures, tackiness at high temperatures, and debris formingproperties of said sheet when subjected to severe environmentalconditions comprising:

fibers contained within said dispersion in an effective amount less thanthe weight of said wax and said additive. 2. The system of claim 1wherein said fibers are selected from the group consisting of polyesterfibers,

acrylic fibers, silk fibers, wool fibers, glass fibers and asbestosfibers.

3. The system of claim 1 wherein said fibers are about A to A inch longand about 2 to 8 denier.

4. In a system comprising a projectile in association with a cartridgehaving a propellant, means for containing said propellant and a rayonsheet impregnated and coated with a dispersion of wax and a wearreducing chemical additive surrounding at least an upper half of saidpropellant, the combination therewith of the improvement for reducingbrittleness at low temperatures, tackiness at Physical properties Propertion, Additive W eight Fin Percent At 40 F. At +1 15 F. Damage,

Percent (Approx) TiO :\/'ax:With0ut Fibers 45:55 Brittle Tacky 10. 0TiO;\Vax:I)acron Fibcrs 4515421 Less brittlc. Less tacky. c.. 0.9TiOyWaxzDacron Fibers 44:54: do "do 0. 9 TiO :Wax:Orlon Fibers 1. 0'IiOyWax: Silk Fibers. 1. 1 TiOz:\Vax:W00l Fibers. 1. 1 TiO zwaxz GlassFibers- 1. 3 TiOgzWZrXzASbeStOS Fibers. 1. 3

In the data above, the sheets, consisting of fabric, wax, fiber andchemical additive, were subjected to a simulated 1000 mile trucktransportation test over extremely rough roads, the sheets having beenmaintained at 40 F. and +l45 F. The physical condition of the sheets wasthen immediately inspected for brittleness at lower temperatures andtackiness at higher temperatures. As can be seen from the data, thesheets without fiber were not high temperatures, and debris-formingproperties of said sheet when subjected to severe environmentalconditions comprising fibers contained within said dispersion.

said fibers constituting about 0.5 to 3.0% by weight of said wax andsaid additive.

5. The system of claim 4 wherein said fibers are selected from the groupconsisting of polyester fibers, acrylic fibers, wool fibers, silkfibers, glass fibers and assufiiciently flexible and produced handlingand assembling 7 bestos fibers.

6 References Cited UNITED STATES PATENTS 6/1960 Brandt l0238 2,940,3913,148,620 9/1964 Jacobson et a1. 10238 3,204,558 9/1965 Jacobson et a1.102-38 BENJAMIN A. BORCHELT, Primary Examiner.

ROBERT F. STAHL, Assistant Examiner.

